[WARNING: The following story contains spoilers from Wednesday's Season 9 finale of Criminal Minds. Read at your own risk.]

The episode promo did not lie. A BAU member indeed left on Wednesday's Criminal Minds season finale: Blake (Jeanne Tripplehorn).

Picking up right in the middle of last week's cliff-hanger shootout that saw Morgan (Shemar Moore) take a bullet in the vest and Reid (Matthew Gray Gubler) get shot in the neck (watch it here), the Season 9 closer opens with Blake tending to a fallen Reid, telling him, "Ethan, open your eyes."

Get the scoop on 39 must-watch season-enders

Who's Ethan? Blake's son, who died at age 9 of a mysterious neurological disease. She spends the rest of the episode staring at a photo of Ethan and feeling guilt-ridden that Reid (who survives) took a bullet while defending her. After the case closes and Blake has a heart-to-heart with Rossi (Joe Mantegna) — during which he reveals that back in the day, his first wife kicked him out after he prioritized his job and forgot their anniversary again — Blake tells Reid about Ethan as she's dropping Reid off at his apartment. "He was ready to go, but I wasn't ready to say goodbye," she says. "The cruelest part was I could see who he'd be at 20, but I knew he'd never get there." As Blake leaves and hails a cab, Reid finds her credentials in his bag.

As for the case, the unsub isn't just one person, but the entirety of a corrupt small-town Texas police force that's led by Deputy Owen McGregor (guest star Michael Trucco) in a plan to target prostitutes who witnessed a staged murder a year prior. Just how dirty are they? One tries to poison Reid in the hospital, but is foiled when Garcia (Kirsten Vangsness) shoots him with Reid's gun. The BAU later takes down McGregor & Co. after an intense showdown in a car junkyard.

So what's the story behind Tripplehorn's exit? Will she be replaced? What did the text message say that Hotch (Thomas Gibson) received on the jet? What can we expect in Season 10? Executive producer Erica Messer answers our burning questions.

How did Jeanne's exit come about? Did she want to leave? Was it mutual?Erica Messer: As things unfold toward the end of the season, when contracts are up and all that stuff, she and I discussed what we wanted to do with the character. We landed on this and Jeanne wasn't interested in a big, flashy exit episode.

For me, the character she's been most connected to emotionally is Reid. Hotch and Rossi have known her longer, but she's closer to Reid — she was the first to know about Maeve and everything. And I just started wondering, "Why is that?" The more I thought about it and because I'm always wondering what makes these characters tick ... I started coming up with she had a child who died and what did he die of and maybe he died of something that wasn't named. As a linguist, that would drive you insane. All of these things started happening and because those two hours [of the two-part finale] are so big and the stakes are high, I felt like the quieter Blake story line would be nice juxtaposition.

Is that why you never announced she was leaving? I think almost everyone was surprised by the promo last week.Messer: Yeah. Jeanne didn't want it to be a big deal and we felt like that was in line with Blake too. I think it makes sense given the character we've known for two years. She's not a splashy, loud character. She didn't come in with a bang — she was already part of the team when we meet her. She came in nicely and she left nicely.

It's definitely the most low-key exit you've had, not counting Seaver.Messer: Definitely. It's funny because on the page it might seem unclear [if she's leaving], but when you see it, you know she's gone. ... The song that we have, which is an original song by Lily Kershaw [the daughter of show director Glenn Kersahw], the very first line is "Let me go," and that plays as Blake's walking down the stairs away from Reid.

Did the message that Hotch received on the jet come from Blake?Messer: It was intended to be a text from her, but we won't know for sure until next season.

Have you talked about a replacement yet?Messer: Not really. We're sort of like, "Let Season 9 end for real and for the world to see it" right now. And then after the summer break, we can all talk about that and what it might be and the wish list and all that. Or maybe the show will continue on with six members. That is a big discussion with a lot of people that we'll have soon.

So it's not definite that she will be replaced?Messer: Right. Every option is possible right now.

Fall Preview: Get your first look at all the new shows

Blake is the third BAU member who's lost a child. JJ (A.J. Cook) had a miscarriage and Rossi's son died the day he was born. Is that purely coincidental, or did you want that to be a common thread between them?Messer: I obviously am aware that the other characters have lost children. Every loss is horrific, but it's a very different thing for a child to be healthy and fine through kindergarten and then all of the sudden they get sick. I have a friend who lost a child at 7 years old. What I saw there was a pain that I couldn't take away for her and I couldn't imagine having. It's a sadness and a way of living that is unlike any other loss. Rossi never got a chance to be a dad. He had an idea and nine months of hoping and wondering. JJ is a mom and didn't have a chance at the second one right then, but hopefully she will one day. So it's a different kind of sadness and you either live it or you know someone's who's lived it.

I think it will resonate in a different way than just simply "they all lost a child." It's a very different sorrow that sort of defines her in many ways. That mothering instinct for her was there. You saw it with her and Reid, but like she said [about Ethan], "I could see what he would look like at 20, but I knew he'd never get there." She sees Reid and thinks her boy could've been like him when he was older. It connects the dots of their relationship. Her not emotionally connecting to cases — she's seen the worst possible thing she could've seen: her child die.

It does inform her character more. She's private and closed-off and does long-distance with her husband.Messer: Exactly. That's what we look at when we realize a character is going to go away. What did we know about them? What have we only thought as the writers? What did the actor think as the character? We've written a lot of people out at this point. [Laughs] So it only makes sense to look at the history of the character and what we know about them and what would make sense in their departure. For her, it was a more emotional exit.

You've had a lot of cast turnover, but you've never killed anyone off.Messer: Just Strauss! Jayne [Atkinson] wasn't a regular though. ... I think killing them off would be a hard thing to do and for an audience member to watch. It was hard with Strauss. I know how connected we are to the characters and fans of the show are too. I feel like it would be the death of a friend if we had to kill anyone off. That seems almost harsh. This way, they can always come back.

What did you think of the promo spoiling that Reid survives and someone was leaving?Messer: I know! I was like, "Wait a minute! We've got to milk that, guys!" [Laughs] But it is kind of a bummer that the promo gave that away. The [exit tease wasn't as bad] because you could still think it was Reid if it didn't show him awake. Obviously he was still in danger after he woke up. ... But I mean, given that any time there is a cliff-hanger like that, everybody watches the promo. The fact that it gave it away, I was like, "What?! Are you crazy?!"

Have you settled on how this whole ordeal will affect Reid? Will he fall off the wagon and abuse Dilaudid again?Messer: My hope is that he doesn't go down the Dilaudid path again! [Laughs] But that's stuff for us to discuss at the beginning of the summer when the writers all come back. That's certainly a very real thing we could make a story out of or just something that we're aware of moving forward. ... Same thing with Garcia shooting someone for the first time. It's interesting because I had written it and I was like, "I should talk to Kirsten before, to make sure she's OK with it." I said, "Here's why. You're saving Reid's life," and she was like, "Right on. Absolutely!" We'll deal with that, but truthfully, she didn't kill him; she just shot him and I feel like when you see the scene, you might be satisfied with the way it is.

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This could be a good link for Reid and his mom if Jane Lynch can come back.Messer: Exactly. I really want to get Jane back again. This will be interesting to see how we pull that off and if it's right away. Because Glee's in its final season, maybe it's something we can't get to until later in the year.

What do you have planned for next season? Messer: Not much yet. There's a version where we pick up the next day. There's a version where we pick up and summertime's gone by just like in real life, so I don't know yet. We're just unplugging from the show in the next few weeks and the beauty of that is when the writers get back together, we can say, "I thought of this. What do you think?" We had such an amazing year. All of the writers are back for Season 10 and it felt like everybody needed to walk away for a bit. These last two episodes took a lot out of everyone. It's a lot of work, but the payoff is great. But everybody needed to enjoy their break this year because last year, we couldn't enjoy it as much since we didn't [get the early renewal], so everybody was afraid to go on vacation and afraid to do anything. This year, the minute we got that pickup, we were like, "OK, we're good? Who wants to go to Paris?" Not like that, but you know. I think Season 10 is going to hold a lot of fun stuff for us to do.

What did you think of the Criminal Minds finale? Who would you like to replace Blake?

(Full disclosure: TVGuide.com is owned by CBS.)

View original Criminal Minds Finale Postmortem: Boss on "Emotional Exit," Replacements and Season 10 at TVGuide.com

Related Articles on TVGuide.com Get the scoop on 39 must-watch season-enders

[WARNING: The following story contains spoilers from Wednesday's Season 9 finale of Criminal Minds. Read at your own risk.]

The episode promo did not lie. A BAU member indeed left on Wednesday's Criminal Minds season finale: Blake (Jeanne Tripplehorn).

Picking up right in the middle of last week's cliff-hanger shootout that saw Morgan (Shemar Moore) take a bullet in the vest and Reid (Matthew Gray Gubler) get shot in the neck (watch it here), the Season 9 closer opens with Blake tending to a fallen Reid, telling him, "Ethan, open your eyes."

Get the scoop on 39 must-watch season-enders

Who's Ethan? Blake's son, who died at age 9 of a mysterious neurological disease. She spends the rest of the episode staring at a photo of Ethan and feeling guilt-ridden that Reid (who survives) took a bullet while defending her. After the case closes and Blake has a heart-to-heart with Rossi (Joe Mantegna) — during which he reveals that back in the day, his first wife kicked him out after he prioritized his job and forgot their anniversary again — Blake tells Reid about Ethan as she's dropping Reid off at his apartment. "He was ready to go, but I wasn't ready to say goodbye," she says. "The cruelest part was I could see who he'd be at 20, but I knew he'd never get there." As Blake leaves and hails a cab, Reid finds her credentials in his bag.

As for the case, the unsub isn't just one person, but the entirety of a corrupt small-town Texas police force that's led by Deputy Owen McGregor (guest star Michael Trucco) in a plan to target prostitutes who witnessed a staged murder a year prior. Just how dirty are they? One tries to poison Reid in the hospital, but is foiled when Garcia (Kirsten Vangsness) shoots him with Reid's gun. The BAU later takes down McGregor & Co. after an intense showdown in a car junkyard.

So what's the story behind Tripplehorn's exit? Will she be replaced? What did the text message say that Hotch (Thomas Gibson) received on the jet? What can we expect in Season 10? Executive producer Erica Messer answers our burning questions.

How did Jeanne's exit come about? Did she want to leave? Was it mutual?Erica Messer: As things unfold toward the end of the season, when contracts are up and all that stuff, she and I discussed what we wanted to do with the character. We landed on this and Jeanne wasn't interested in a big, flashy exit episode.

For me, the character she's been most connected to emotionally is Reid. Hotch and Rossi have known her longer, but she's closer to Reid — she was the first to know about Maeve and everything. And I just started wondering, "Why is that?" The more I thought about it and because I'm always wondering what makes these characters tick ... I started coming up with she had a child who died and what did he die of and maybe he died of something that wasn't named. As a linguist, that would drive you insane. All of these things started happening and because those two hours [of the two-part finale] are so big and the stakes are high, I felt like the quieter Blake story line would be nice juxtaposition.

Is that why you never announced she was leaving? I think almost everyone was surprised by the promo last week.Messer: Yeah. Jeanne didn't want it to be a big deal and we felt like that was in line with Blake too. I think it makes sense given the character we've known for two years. She's not a splashy, loud character. She didn't come in with a bang — she was already part of the team when we meet her. She came in nicely and she left nicely.

It's definitely the most low-key exit you've had, not counting Seaver.Messer: Definitely. It's funny because on the page it might seem unclear [if she's leaving], but when you see it, you know she's gone. ... The song that we have, which is an original song by Lily Kershaw [the daughter of show director Glenn Kersahw], the very first line is "Let me go," and that plays as Blake's walking down the stairs away from Reid.

Did the message that Hotch received on the jet come from Blake?Messer: It was intended to be a text from her, but we won't know for sure until next season.

Have you talked about a replacement yet?Messer: Not really. We're sort of like, "Let Season 9 end for real and for the world to see it" right now. And then after the summer break, we can all talk about that and what it might be and the wish list and all that. Or maybe the show will continue on with six members. That is a big discussion with a lot of people that we'll have soon.

So it's not definite that she will be replaced?Messer: Right. Every option is possible right now.

Fall Preview: Get your first look at all the new shows

Blake is the third BAU member who's lost a child. JJ (A.J. Cook) had a miscarriage and Rossi's son died the day he was born. Is that purely coincidental, or did you want that to be a common thread between them?Messer: I obviously am aware that the other characters have lost children. Every loss is horrific, but it's a very different thing for a child to be healthy and fine through kindergarten and then all of the sudden they get sick. I have a friend who lost a child at 7 years old. What I saw there was a pain that I couldn't take away for her and I couldn't imagine having. It's a sadness and a way of living that is unlike any other loss. Rossi never got a chance to be a dad. He had an idea and nine months of hoping and wondering. JJ is a mom and didn't have a chance at the second one right then, but hopefully she will one day. So it's a different kind of sadness and you either live it or you know someone's who's lived it.

I think it will resonate in a different way than just simply "they all lost a child." It's a very different sorrow that sort of defines her in many ways. That mothering instinct for her was there. You saw it with her and Reid, but like she said [about Ethan], "I could see what he would look like at 20, but I knew he'd never get there." She sees Reid and thinks her boy could've been like him when he was older. It connects the dots of their relationship. Her not emotionally connecting to cases — she's seen the worst possible thing she could've seen: her child die.

It does inform her character more. She's private and closed-off and does long-distance with her husband.Messer: Exactly. That's what we look at when we realize a character is going to go away. What did we know about them? What have we only thought as the writers? What did the actor think as the character? We've written a lot of people out at this point. [Laughs] So it only makes sense to look at the history of the character and what we know about them and what would make sense in their departure. For her, it was a more emotional exit.

You've had a lot of cast turnover, but you've never killed anyone off.Messer: Just Strauss! Jayne [Atkinson] wasn't a regular though. ... I think killing them off would be a hard thing to do and for an audience member to watch. It was hard with Strauss. I know how connected we are to the characters and fans of the show are too. I feel like it would be the death of a friend if we had to kill anyone off. That seems almost harsh. This way, they can always come back.

What did you think of the promo spoiling that Reid survives and someone was leaving?Messer: I know! I was like, "Wait a minute! We've got to milk that, guys!" [Laughs] But it is kind of a bummer that the promo gave that away. The [exit tease wasn't as bad] because you could still think it was Reid if it didn't show him awake. Obviously he was still in danger after he woke up. ... But I mean, given that any time there is a cliff-hanger like that, everybody watches the promo. The fact that it gave it away, I was like, "What?! Are you crazy?!"

Have you settled on how this whole ordeal will affect Reid? Will he fall off the wagon and abuse Dilaudid again?Messer: My hope is that he doesn't go down the Dilaudid path again! [Laughs] But that's stuff for us to discuss at the beginning of the summer when the writers all come back. That's certainly a very real thing we could make a story out of or just something that we're aware of moving forward. ... Same thing with Garcia shooting someone for the first time. It's interesting because I had written it and I was like, "I should talk to Kirsten before, to make sure she's OK with it." I said, "Here's why. You're saving Reid's life," and she was like, "Right on. Absolutely!" We'll deal with that, but truthfully, she didn't kill him; she just shot him and I feel like when you see the scene, you might be satisfied with the way it is.

Add new fall shows to your Watchlist!

This could be a good link for Reid and his mom if Jane Lynch can come back.Messer: Exactly. I really want to get Jane back again. This will be interesting to see how we pull that off and if it's right away. Because Glee's in its final season, maybe it's something we can't get to until later in the year.

What do you have planned for next season? Messer: Not much yet. There's a version where we pick up the next day. There's a version where we pick up and summertime's gone by just like in real life, so I don't know yet. We're just unplugging from the show in the next few weeks and the beauty of that is when the writers get back together, we can say, "I thought of this. What do you think?" We had such an amazing year. All of the writers are back for Season 10 and it felt like everybody needed to walk away for a bit. These last two episodes took a lot out of everyone. It's a lot of work, but the payoff is great. But everybody needed to enjoy their break this year because last year, we couldn't enjoy it as much since we didn't [get the early renewal], so everybody was afraid to go on vacation and afraid to do anything. This year, the minute we got that pickup, we were like, "OK, we're good? Who wants to go to Paris?" Not like that, but you know. I think Season 10 is going to hold a lot of fun stuff for us to do.

What did you think of the Criminal Minds finale? Who would you like to replace Blake?

(Full disclosure: TVGuide.com is owned by CBS.)

View original Criminal Minds Finale Postmortem: Boss on "Emotional Exit," Replacements and Season 10 at TVGuide.com

Related Articles on TVGuide.com Get the scoop on 39 must-watch season-enders